Certain embodiments of the present invention generally relate to connectors that electrically connect components to one another and more particularly relate to an electrical connector assembly having contacts arranged in differential pairs.
Various electronic systems, such as those used to transmit signals in the telecommunications industry, include connector assemblies that electrically connect differential pairs of electrical wires with each other or differential pairs of electrical wires to electrical plugs. The telecommunications industry uses an unshielded twisted pair (UTP) system where one wire in the differential pair carries a positive signal and the other wire carries a negative signal. The differential pair does not include a ground, but instead carries signals intended to have the same absolute magnitude. The connector assemblies include insulated housings having contact channels that hold contacts (e.g., insulation displacement contacts (IDCs)). The IDCs have top and bottom ends configured to pierce insulation that surrounds wires inserted into the IDCs in order that the IDCs electrically engage corresponding conductive wires. The contact channels in the housing are arranged such that IDCs are maintained within the housing in differential pairs. One IDC in each differential pair connects two wires that carry positive signals. The other IDC in each differential pair connects two wires that carry negative signals.
However, conventional connector assemblies have several drawbacks. First, the IDCs of different differential pairs are positioned proximate each other such that unwanted electromagnetic (EM) signal coupling, or cross talk, develops between the IDCs of differential pairs of IDCs. The cross talk degrades the quality of the signal transmissions such that the electrical signals may not be deciphered at their destination. Some connector assemblies have been proposed that afford EM shielding by providing metal shields between the differential pairs of IDCs. The shields act as barriers to electrically isolate the differential pairs of IDCs and prevent unwanted EM signal coupling between IDCs of adjacent differential pairs. The EM signals cause the shields to collect a capacitive charge. Conventional connector assemblies discharge the capacitive charge by connecting the shields to ground.
Further, because the IDCs in a differential pair have different geometries from the wires in a differential pair, the electrical signals experience a different impedance when traveling through the differential pairs of IDCs than when traveling through the differential pairs of wires. This mismatched impedance causes a portion of the electrical signals to be reflected back toward its source. The amount of reflection that occurs due to a change in impedance is considered a return loss.
In certain industries, standards are set for performance requirements of electrical connector assemblies, including a bandwidth for the transmission of signals. New standards have increased the maximum frequency of the bandwidth such that many conventional connector assemblies exhibit too much cross talk and return loss to meet the more stringent frequency requirements.
Thus, a need exists for a connector assembly that reduces cross talk and return loss in a connector assembly holding multiple differential pairs of IDCs.
Certain embodiments provide a connector assembly including a housing having a top end and a bottom end with contact channels extending through the housing. The connector assembly also includes contacts provided in the contact channels that are arranged in differential pairs. The connector assembly includes an electrically common shield having dividers mounted in the housing to separate adjacent differential pairs of the contacts. The electrically common shield is isolated from ground.
Optionally, a plurality of planar divider shields are arranged in an interleaved manner between the differential pairs of contacts. First and second contacts within a differential pair introduce positive and negative charges onto first and second divider shields, respectively. The positive and negative charges introduced onto the first and second divider shields substantially negate one another to form a substantially zero net charge.